I just replaced mysql-connector-java-3.1.7-bin.jar with the old one 3.1.6 due to very stange problems....
That was what I had thought. I had change the Coonector/J to 'mysql-connector-java-3.0.16-ga-bin.jar' and the problem was still the same. This problem is weird as it seems there is no problem to connect to the MySql server and no problem of finding the database, but the table. The table and records are there, I can see them from the client console of MySql. While, any clue are welcome.